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87 terms

Electrical Wiring Diagram Symbols

Electrical Wiring Diagram Symbols commonly found in HVAC wiring diagrams
STUDY
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High Voltage, Factory Wired
Low Voltage, Factory Wired
High Voltage, Field Wired
Low Voltage, Field Wired
High Pressure Switch
Normally Closed
Opens on increase (rise)/Closes on decrease (drop)
(vacuum & pressure activated)
Low Pressure Switch
Normally Open
Closes on increase (rise)/Opens on decrease (drop)
(vacuum & pressure activated)
Cooling Thermostat
Normally Open
Closes on increase (rise)/Opens on decrease (drop)
(temperature activated)
Heating Thermostat
Normally Closed
Opens on increase (rise)/Closes on decrease (drop)
(temperature activated)
High Liquid Level Switch
Normally Closed
Opens on increase (rise)/Closes on decrease (drop)
(liquid level activated)
Low Liquid Level Switch
Normally Open
Closes on increase (rise)/Opens on decrease (drop)
(Liquid Level activated)
Flow Switch (positive)
Normally Open
Closes on flow or movement
(air, water, liquid flow or movement)
Flow Switch (negative)
Normally Closed
Opens on flow or movement
(air, water, liquid flow or movement)
Normally Open Contacts
Normally Closed Contacts
Disconnect Switch
Magnetic Circuit Breaker
Series Trip
Thermal Circuit Breaker
Series Trip
Normally Open Spring Return Limit Switch
Normally Closed Spring Return Limit Switch
Held Closed Spring Return Limit Switch
Held Open Spring Return Limit Switch
Neutral Position Spring Return Limit Switch
Maintained Position Limit Switch
Selector Switch
Slide Switch
Cam Activated Swtich
Single Pole Single Throw Switch
Single Pole Double Throw Switch
Single Pole Double Throw 3 Position Switch
Double Pole Double Throw Switch
Push Button
Normally Open
Single Circuit
Momentary, Spring Return
Push Button
Normally Closed
Single Circuit
Momentary, Spring Return
Momentary Push Button
Double Circuit
Momentary, Spring Return
Maintained Push Button
Double Circuit
Normally Opened Energized Time Contact
Contact action retarded when coil is ENERGIZED
Normally Closed Energized Time Contact
Contact action is retarded when coil is ENERGIZED
Normally Open De-energized Time Contact
Contact action is retarded when coil is
DE-ENERGIZED
Normally Closed De-energized Time Contact
Contact action is retarded when coil is
DE-ENERGIZED
Fixed Resistor
Glow Coil
Strip Heater
Variable Resistor
Tapped Resistor
Thermistor
Heater type Resistor
Transformer
(variants)
Capacitor
Coil
(variants)
Fuse
Fusible Link
Ground Connection
Light
Multiple Conductor Cable
Thermocouple
Thermal Overload
Bi-Metal Switch
Connectors
Electrode
Ignitor
Crank Case Heater
Meter
* denotes type
Variable Inductor
Fixed Inductor
Solenoid
Multi Pole Double Throw Switch
Multi Pole Single Throw Switch
Electrically Operated Switch
* Indicates magnetic coil,motor, or thermal element
Foot Switch
Normally Open
Foot Switch
Normally Closed
Auto Transformer
Current Transformer
Variable Transformer
Transformer - Auto Adjustable Tapped
Fixed Iron Core Coil
Fixed Air Core Coil
Adjustable Iron Core Coil
Adjustable Air Core Coil
Motor
Single Phase
2 Lead
Motor
Single Phase
3 Lead
Motor
3 Phase
3 Lead
Motor
3 Phase
6 Lead
Dual Windings
Bi-Metallic Thermal Overload
Bi-Metallic Thermal Overload
with heater
Microphone
Diode
Headset
Horn or Siren
Buzzer or Bell
Push to Test Lamp
Shielded Cable